Yang, Z (reprint author), Tsinghua Univ, Dept Engn Phys, Ctr High Energy Phys, Room 429, Beijing 100084, Peoples R China.
The Hanbury-Brown and Twiss (HBT) effects predict a Bose-Einstein enhancement of the two-particle momentum correlations of identical bosons at small relative momentum. However, the parallel momentum correlations between identical fermions are less argued. The momentum correlations can be altered by many factors, among which the spin interaction effects are discussed in this paper. It is found that the spin interaction plays an important role on the momentum correlations of identical fermions. For spin triplet state, a full Fermi-Dirac suppression represents as expected. On the contrary, a fake Bose-Einstein enhancement shows up for spin singlet state. The measured momentum correlations of fermions could hence provide some hints of spin interactions between them if all other factors such as Coulomb interactions were removed. Spin interactions make it more complicated to extract physical information from momentum correlations between fermions.